In the construction of buildings and mechanical systems, a newly installed or repaired fluid transfer system or system component, as for example a building plumbing or sewage system, must frequently be isolated from a larger system until the fluid-tight integrity of the new section is tested, generally by subjecting the system to an increased fluid pressure to locate any leaks. In building construction, system tests of this kind are often required for certification of compliance with building code requirements. The inherent difficulty of making such pressure tests is often aggravated by the fact that some portion of the new installation is embedded in a wall or is buried, obstructed by other components, or otherwise difficult to access at the time the test is to be conducted. Thus a vexing question has been posed by the need to seal selected portions of such systems in order to accommodate testing without permanent obstruction or other damage to the system.
Various attempts have been made at providing systems or means for conducting such tests. In particular, several patents have been issued disclosing test or isolation valve assemblies used in the inspection of drain systems prior to connection of the systems to sewer lines.
Sullivan U.S. Pat. No. 4,429,568, discloses a closure plug for pressure testing a liquid drain and vent plumbing type system. Sullivan uses a clean-out Y for access to open the plug plate assembly.
Cohen U.S. Pat. No. 1,720,819, discloses a test tee having a tapered gate which closes off a house drain pipe from a drainage system. After the test has been completed, the gate is removed from the test tee and the resulting opening in the tee is closed by a cover plate.
Tagliarnio U.S. Pat. No. 4,542,642, discloses a test tee having a plug which is a removable blocking disk. The blocking disk engages a ledge in the test tee and seals the drainage system. The diaphragm is accessible and removable through an access means.
Roberson U.S. Pat. No. 4,658,861, discloses a pneumatic plug inserted through a clean-out tee to block off a house service line to the main sewer line.
Kennedy U.S. Pat. No. 1,948,220, discloses a test plumbing system using a flap valve which is pivoted at an upper side of the valve seat. The flap valve is held in position by a valve adjusting rod.
Barber U.S. Pat. No. 4,602,504, shows a permanently installed test fitting in which a seal diagram has a frangible, removable portion which may be broken away from the diaphragm and removed to permit service use of the system. A portion of the seal diaphragm remains permanently in the conduit with its edge exposed, posing a continuous threat of blockage and obstruction. Moreover, improvements in the sealing means disclosed in Barber would better suit the test fitting for use as a permanent, fully functional, non-leaking portion of the fluid transfer system in which it is used. In addition, Barber discloses no means for removing the sealing means through an extended length of installed fluid line. Barber U.S. Pat. No. 4,706,482 adds to this apparatus for monitoring pressure within the test portion of the fluid line.
Nachtigahl U.S. Pat. No. 4,194,721 discloses a plumbing test fitting having a closure plate adapted to be slidably fitted between a pair of spaced adjacent ends of a pair of pipes, the joint being sealed by a detachable sealing clamp which also sealably bears against the periphery of the closure plate. A test fitting of this type is not well adapted to permanent placement in the fluid line, so that a fluid-tight system, once tested, would have to be disturbed and re-worked once testing was complete.
Hasha U.S. Pat. No. 4,132,111 discloses a method and apparatus for leak testing. The Hasha apparatus comprises a system of annular longitudinally-spaced sealing members disposed on the exterior of the pipe to test the integrity of joints without attempting to stay fluid flow in the interior of the fluid line.
Miller U.S. Pat. No. 3,712,115 discloses pipe testing apparatus comprising a pair of upper and lower elongate spacer bar to form a pipe testing assembly.
These references relate to the general field of disclosure of this invention but many suffer from the permanent presence of apparatus in the conduit which can catch refuse and cause pluggage.
More recently, U.S. Pat. Nos. 4,848,155,4,936,350, 5,033,510, and 5,163,480 to Huber have disclosed various apparatus for isolating and testing plumbing installations. It has been noted, however, through usage of the devices disclosed therein, that improvements might be made in the effectiveness of the seal provided in the test section, particularly by the test baffle and around the test device itself, and in means and method for removal of the baffle after the test has been completed. It has also proved possible to improve the flexibility of the baffles disclosed therein, without sacrificing the strength or pressure-resistant capabilities of the baffles, in order to facilitate easier and more efficient removal of the baffles from the fluid line following testing.
Other attempts have included glued-in or molded "cookies" to seal flow within a pipe, in the same general manner as the baffles described in the Huber references above, and inflatable balloon inserted into the fluid line and filled with air or water to block flow. "Screw-in" threaded type plugs have been tried as well, as have dual-plate devices comprising a pair of flat plates attached through their centers by a coaxial tightening device. But glued or molded cookies are often inconvenient to use, and after removal leave behind portions of the baffle which thereafter permanently block part or all of the flow within the fluid line; and they also not infrequently get stuck themselves on removal, requiring dismantlement of the fluid line itself or causing permanent flow obstructions. Inflatable balloons rarely seal the fluid line effectively, especially under moderate or high pressures, such that leakage is a common and continual problem, and testing is rarely fully effective--and typically messy or hazardous, as leaked fluid must be cleaned up or (in the case of gasses) is irretrievably introduced to the atmosphere, Threaded plugs rarely allow testing of an installed system in the form in which it will be used, thus providing at best incomplete test results; and dual-plate devices, which generally comprise substantially rigid plates having flexible polymeric perimeters, often seat themselves on dirt, rust, and other irregularities or obstructions within the fluid line, resulting again in leakage and incomplete or inaccurate testing as well as clean up or environmental hazards.
Thus it may be seen that there exists a need for an improved system for the non-destructive and non permanently-obstructing testing of the fluid tight integrity of an installed fluid transfer line such as a drain pipe or vent and wastewater system of a building. In particular, there is a need for the provision of such a system in a simple and economical form which provides an improved permanent external seal and which makes use of an improved test baffle. There is additional need for such a system which does not require the employment of a T- or Y-fitting for access to or removal of the test baffle, or for separate access covers, and which does nor require the replacement of parts or seals following completion of the test or the use of pneumatic or otherwise inflatable apparatus in performing the test.